With the emergence of complex organic contaminants resilient to conventional water purification methods, alternative advanced treatment techniques, such as membrane filtration, adsorption, and photocatalysis have come under heavy research. Notably, titanium dioxide, a wide band-gap semiconductor with the capability of producing reactive oxygen species in water under UV radiation has proved effective for degrading organic materials while producing benign CO2 as an end product. This ability to remove contaminants completely and efficiently combined with low cost, low toxicity, and high abundance make it a beneficial treatment platform for dealing with organic pollutants. However, despite the existence of commercial TiO2 formulations with excellent photocatalytic efficiency, they have found minimal use in industrial or commercial water treatment. One of the principal reasons for this is the difficulty associated with recovering nano-scale dispersions of the catalyst for re-use, diminishing the potential efficiency of the catalyst and posing an environmental threat due to the release of the catalyst into natural bodies of water.
Various techniques have been investigated in an attempt to address this issue including immobilization of TiO2 nanomaterials on various substrates such as sand, glass or polymer beads and membranes. While these techniques solve the problems associated with TiO2 separation after treatment, they simultaneously introduce other problems related to photocatalytic efficiency, such as limiting dispersion of the catalyst throughout the solution thereby limiting interaction with contaminants.
Therefore, there is provided a novel modular method and apparatus for producing recyclable photocatalytic particulates.